Then the Bay Area-built spectrometers will study the tiny puff of pulverized rock that's sent into the air and detect what elements made up that piece of rock.

Knowing those elements can give NASA scientists an incredible understanding of how Mars formed, how wet and Earth-like it once was, what changed to make it so dry and rocky, and whether it could have ever supported life.

The sensors work by splitting light into a rainbow. The amount of each color you learned in kindergarten -- red, orange, yellow, green, blue, indigo, and violet -- can tell scientists exactly elements are in each sample.

To give us a demo here on Earth, they zapped a penny in a test chamber.

No surprise -- it's made of mostly copper -- but the ability to know that answer in seconds, plus see all of the other metals that are also there in tiny amounts, is a recipe for scientific breakthroughs.

The project's been in the works since 2004. Much of that time's been spent with another scientist, Dave Landis, making sure these top-of-the line tools are rugged enough for a wild ride to the Red Planet.

"It's a lot different swimming the English Channel than swimming in your pool," Ocean Optics Chairman Rob Randelman said, comparing the challenges of building a scientific instrument for a rocket trip to Mars versus one for use on Earth.

"The vibration testing, the cosmic ray testing -- it has to be rugged and durable," Randelman said.

"You don't get repairmen to come up to Mars to fix things. And you have to make sure -- way ahead of time -- that everything's going to work perfectly the very first time."